Coil-forming machine with generator controlled spindle positioning means



Jan. 13, 1959 T. E. LEWIS, JR.. ET AL COIL-FORMING MACHINE WITH GENERATOR CONTROLLED SPINDLE POSITIONING MEANS 6 Sheets-Sheet 1 Filed Feb, 4. 1954 INVENTORS E Lew/3J1 ida/ A. Z ave/ 111 10 W M unk ATTORNEYS Jan. 13, 1959 T. E. LEWIS, JR. ET AL 2,868,268

COIL-FORMING MACHINE WITH GENERATOR CONTROLLED SPINDLE POSITIONING MEANS 6 Sheets-Sheep 2 Filed Feb. 4, 1954 INVENTORS i l r MW a LZ A w mm MW mfi A T O EEZYS Jan. 13, 1959 T. E. LEWIS, JR. ET AL 2,868,268

COIL-FORMING MACHINE WITH GENERATOR CONTROLLED SPINDLE POSITIONING MEANS Filed Feb. 4, 1954 6 Sheets-Sheet 3 HEADSTOCK DRIVE 3 510 H MRA STOP START 53 I MANDREL DR-IVE STOP START ECRZ R E RETURN :2 SST e1- TRT1 TE P70 CHUCKS LAYDOWN ROLL- CIZR CIZRb: CRRC Z CRRdlI.

INVENTORJ Thomas E. LewisJn Vic 20/" A. Za veru 71a,

Jan. 13, 1959 T. E. LEWIS, JR; ETAL 2,868,268

COIL-FORMING MACHINE WITH GENERATOR CONTROLLED SPINDLE POSITIONING MEANS 6 Sheets-Sheet 5 Filed Feb. 4. 1954 a III E w |..1|.\. m mu 5 R \1 6 i. .9 .n w i l 7 I n 0 4m 4 W PM 3 I 8 a 7. A J a i I W m V Z fl Z k \fl l I M. y 4 W m ...i1 H HWm IH MHWMHIMWMIW W M m I ATTORNEYS Jan. 13, 1959 T. E. LEWIS, JR.. ET AL ,3 8,

I COIL-FORMING MACHINE WITH GENERATOR CONTROLLED SPINDLE POSITIONING MEANS F iled Feb. 4. 1954 6 Sheets-Sheet 6 INVENTORS Thomas E. Lewis Jfl Victor A. Zaver'uka ATTORNEYS United States Patent COIL-FORMING MACHINE WITH GENERATOR CONTROLLED SPINDLE POSITIONING MEANS Thomas E. Lewis, .Fr. and Victor A. Zaveruha, Trumbull, Conn., assignors to The Coulter & McKenzie Machine Co., Inc., Bridgeport, Conn., a corporation of Con- This invention relates to an improved coil-winding or forming machine of the type used in the formation of coil springs or the like.

It is an object of the present invention to provide a coil-forming machine capable of winding coils of various sizes and design quickly and accurately.

Another object of the invention is to provide an improved means for locating the winding spindle in a predetermined starting position.

Another object of the invention is to provide an improved chuck for gripping the first end of the stock forming the coil to insure a tight and square first end down to the tapered point without projections beyond the outside diameter of the coil.

Another object of the invention is to provide a coiling machine with a novel mandrel construction which is long-wearing and free-stripping.

Another object of the present invention is to provide accurate control for starting the coil-laying carriage so that the first coil can be made to form any desired flat base extending through any portion up to substantially a complete turn thereof whereby a flat end for the spring may be provided.

Another object is to provide improved stripping means whereby the coil is removed from the mandrel without distortion, change of length or position of turns.

Another object of the invention is to provide a novel method of coiling and controlling the operation of the elements in forming the coil.

A feature of the invention resides in the unique control of the spindle during the reset period by control of the clutch and brake in the drive therefor whereby the spindle can be set to a predetermined starting position quickly and accurately without overrunning the position.

Another feature of the invention resides in the smooth, freely rotatable mandrel which is adapted to receive the coil in any position on the surface, thus eliminating grooving of the mandrel by the repeated winding of the coil on the same surfaces on the mandrel and the necessity to reset the mandrel. The mandrel is rotated during the coiling operation by the stock forming the coil and gripping the mandrel as the stock is being coiled around the mandrel by the rotation of the chuck, thus eliminating the necessity for a drive for the mandrel. Further, since a grooved mandrel is not used to position the coils, the smooth mandrel of the present invention permits infinite variation in coil pitch or turn relations as they are formed thereon.

A further feature of the invention resides in the positive drive for the mandrel to rotate the same relative to the coil wound thereon during a stripping operation which releases the coil from gripping relation with the mandrel and permits the mandrel to be extracted from the coil without distortion of the coil.

A still'further feature of the invention resides in the control for the chuck and the lay-down roller for forming the other end of the coil whereby they hold the coil during the initial mandrel extracting operation and resist any distortion of the coil during the initial extracting period.

Another feature resides in the control system which can be manually orautomatically actuated during a forming cycle to produce the coil spring as desired.

Other features and advantages of the invention will be apparent from the specification and claims when considered in connection with the drawings in which:

Figure 1 shows a side view of the machine.

Fig. 2 is a schematic view of the machine showing the main elements, drive means therefor, and control means for the elements of the machine.

Figs. 3 and 4 show the wiring diagram for controlling the various elements of the machine.

Fig. 5 is a sectional view on an enlarged scale taken on line 55 of Fig. 1.

Fig. 6 is a longitudinal view through the chuck mounted on the end of the headstock or winding spindle.

Fig. 7 is a detail view of the lay-down roller and stripping fingers.

Fig. 8 shows diagrammatically the relation of the spindle, chuck and mandrel during formation of the coil.

Fig. 9 is a view similar to Fig. 8 showing the elements at the completion of the coil.

Fig. 10 shows the elements at the beginning of the stripping operation.

Fig. 11 shows the elements at the time the coil is released by the chuck and lay-down roller during the stripping operation.

As shown in Fig. l, the machine comprises a base 10 having a headstock 11 at one end and a tailstock 12 at the other. The headstock has a'headstock spindle 13 driven by a reversible headstock motor HM through a drive including an electromagnetically operated clutch C1 and brake B1 and variable speed gearing 14. An hy draulically operated chuck 15 is mounted on the end of the headstock spindle for gripping the tapered end of a bar of stock 16 asit is inserted into the machine. As shown in Figs. 1, 2, 5 and 6 the chuck comprises a housing 17 mounted on the flange 13a of the headstock spindle 13. A gripping jaw 18 has a curved face 18a and is adjustably carried by a slide 19 mounted on the housing for sliding movement transversely thereof so as to grip the end of the coil against a boss 20 projecting from the face plate 21 of the housing and functioning as a mandrel extension to receive the first turn of the coil.

The actuator for the slide comprises a pivoted bell crank 22.having one end 2212 connected to the slide and the other end 22b connected to a draw bar 23 actuated by a piston 24 in a cylinder 25 at the end of the headstock spindle. The cylinder is connected to a source of fluid so as to be in normally released position and when actuated by a solenoid valve 8V1, connected in the control circuit, Withdraws the rod causing the chuck to grip the end of the stock as shown in Fig. 6.

The tailstock 12 has a mandrel 26 mounted thereon to project toward and be in alignment with the winding spindle and is mounted on the bed for movement toward and away from the headstock. This is accomplished by means of a reversible tailstock motor TE connected through an electromagnetic clutch C3 to a worm 27 for rotating a gear 28 in engagement with a rack 29 on the tailstock. An electromagnetic brake B3 is employed to hold the tailstock in any adjusted position.

The mandrel is mounted for free rotation on the tailstock and is adapted to be connected to a reversible driving motor MM mounted on the tailstock by means of an electromagnetic clutch C5. The mandrel is moved to winding position by the tailstock. This is accomplished by energizing the tailstock motor TE. The tailstock moves rapidly toward the headstock. At a point just prior to the engagement of the mandrel with the chuck, the tail 3 stock actuates limit switch LSd, shifting the control for the clutch C3 and brake B3 in the tailstock drive to a slow speed drive circuit controlled by a generator G2 driven from the'motor TE for the tailstock. The generator generates a voltage in accordance with the speed of the tailstock drive and is connected, to a bridge 3R2 which bridge controls an electronic relay ECR2. The electronic relay is set so that when the generated voltage is less than a predetermined amount the clutch C3 is operated'to move the. tailstock forward. When it exceeds said predetermined amount, the brake B3 is operated until the speed drops below the predetermined amount and the clutch is again operated. Thus the tailstock is inched forwardly at a slow speed until the reduced end 26a of the mandrel is inserted into the bore Ztla in the boss 26) on the chuck at which time limit switch LS3 is actuated to open the circuit to clutch C3 and apply the brake B3. By utilizing this controlled speed, the mandrel is prevented from jamming up against the chuck and causing damage to the machine.

In order to properly position the coils of the spring, a traverse or coil-laying carriage 30 is mounted to slide on an upper bed 31 of the machine. The carriage is moved along the upper bed by means of a gear 32 engaging a rack 33. The gear 32 is driven by chain drive 32 from gear 32a slidable along a drive shaft 34 normally driven from the headstock motor HM through a variable speed drive 35, an electromagnetically operated clutch C2 and a set of tumbling gears 36 for reversing rotation of the drive shaft to secure proper feed for right or left-hand wound coils as may be desired. The carriage is provided with a roller 38, mounted on a support 38a which is adjustably mounted on ribbed face member Stia for adjustment toward and away from the mandrel by bolts 3% positfoned in slots 38b in the support and secured in apertures 30: in the face member. The face member 30a is secured to the carriage for vertical adjustment by bolts 30d disposed in slots Idle on the carriage. The roller is adjusted to engage the stock 16 and advance it along the mandrel as the coil is wound. Inasmuch as the carriage is driven from the headstock motor HM during the winding operation, its movement can be controlled accurately by proper adjustment of the variable speed drive to produce the proper pitch on the coil being wound.

In order to return the carriage to starting position independently of the operation of the headstock spindle, a motor TR is provided which is geared at 39 to the drive shaft 34 through an electromagnetically operated clutch C4. The clutch C4 is energized when the tailstock is actuated to move the mandrel into winding position and moves the carriage to initial starting position. When it reaches this position, it engages limit switch LS1 opening the circuit to clutch C4.

In order to properly locate the headstock or winding spindle for the beginning of each winding operation, the present invention provides a novel and accurate system which is controlled by the position of the winding spindle and arranged, as shown in Fig. 2, to control the position of the chuck to receive the end of the stock. This system comprises a generator G1 driven from the, drive for the headstock spindle, which generator is connected to a bridge circuit BRA so that the, generator voltage is impressed on the bridge circuit. The bridge circuit controls an electronic control relay ECRl which is adjusted so that when the spindle speed is below a predetermined low speed it will cause the clutch C1 to the spindle to be energized and drive the spindle. As soon as the spindle exceds said predetermined speed, the bridge causes the electronic relay to open the clutch circuit and apply the brake B1 until the speed drops below said predetermined speed. While this process may be repeated for as many or few turns as required, it is herein illustrated as operating only until the spindle has been rotated through a pan messes tial rotation to its desired position, in which position a lug 40 carried by a cam plate 41 mounted on the spindle engages a limit switch LS6 to open the circuit to the spindle clutch Cl and apply brake B1. This will be more fully explained in the operation of a cycle of the machine hereinafter.

The present invention also provides a lay-down roller 42 which is shown in detail in Fig. 7. The roller is adapted to engage the end of the stock and lay the last turn into a flat ended coil and is mounted on an arm 43 pivoted by pivot 43' on a bracket 44 mounted adjacent the mandrel. The arm is connected by a link means 45 to a piston 46 operating in cylinder 47. The roller is normally held in raised position, as shown in dotted lines, and is moved into engagement with the mandrel, as shown in full lines in Fig. 7, when the solenoid valve 8V4 is energized to supply actuating fluid to the cylinder as will' hereinafter be described.

Preferably the roller is moved into engagement with the mandrel subsequent to the time that the chuck is operated to grip the leading end of the stock so that the machine is ready for the winding of the coil.

The present invention provides means for controlling the forming of the first turn of the coil so as to provide a fiat bottomed coil. This is accomplished by providing on the spindle shaft a second cam plate 48 having thereon a lug 49 positioned in a predtermined angular relation with respect to the initial position of the spindle. Lug 49 is adapted to engage limit switch LS5 to close a circuit to clutch C2 to initiate the movement of the carriage 30 after said predetermined rotation of the spindle from starting position. The position of the lug 49 can be angularly adjusted with respect to lug 40 from 0 to substantially 360. Thus, when the controller for the coiling operation is held closed the spindle will rotate and the chuck-hdding end of the stock will cause it to be wound around the boss in a fiat first coil until the lug 49 on the cam plate 48 operates the limit switch LS5 to energize the clutch C2 in the carriage drive whereupon the carriage and its guide roller 33 move longitudinally of the man drel to coil the stock therearound.

During the winding or forming operation the clutch C5 is not energized so that the mandrel is a freely rotatable mandrel and is rotated by the stock as the same is wound therearound by the chuck gripping the end of the stock. This permits the coil to be wound tightly on the mandrel so that an accurate outside diameter can be maintained, eliminates the need for a drive means for the mandrel during this operation and eliminates the necessity for reset-- ting the mandrel to a predetermined position.

A further advantage present in the machine of the present invention resides in the fact that with a smooth mandrel, in contradistinction to the grooved mandrels heretofore used and into which groove the stock is laid to form the coil, the, present invention is capable of winding coils of any pitch by proper adjustment of the variable speed drive 35 for the carriage since the entire smooth surface of the mandrel is capable of receiving the stock.

The traverse carriage controls the laying of the coil on the mandrel until the full length is wound. It then engages limit switch LS2 which automatically stops its movement.

The coiling controller switch is then released and the winding spindle stops and the brake B1 applied. The machine is now ready for a stripping operation. This is accomplished by holding the strip switch closed. This first causes the clutch C5 in the mandrel circuit to be energized and the mandrel rotated with respect to the end of the coil which is held stationary by the chuck on the headstock spindle. The mandrel is rotated in such a direction with respect to the coil as to free the coil from gripping engagement with the mandrel. After a predetermined time the tailstock motor TB is reversed and the tailstock moves back withdrawing the mandrel from the coil. During this part of the stripping cycle the coil is held against movement by the headstock and laydown roller. When the mandrel has been substantially fully extracted from the coil, the tailstock engages a limit switch LS9 which deenergizes solenoid valves SVl and 8V4 and releases the chuck and laydown roller and trees the coil. Stripping fingers 50 are mounted on bracket 44 for adjustment thereon by pivots 50a and are clamped by bolts 50b, operating in slots 50c, in position to engage the end of the coil, preferably after a predetermined outward movement thereof, and hold it against movement as the mandrel is completely withdrawn by the taiistock, dropping the coil spring to any suitable conveyor, not shown, for removing the springs from the machine. As the tailstock reaches the withdrawn position, it engages limit switch LS4 which deenergizes clutch C3 and applies brake B3.

The operation and control of the machine can best be understood from a consideration of a cycle thereof for winding a right-hand coil. With the selector switch SS moved to the upper or wind right position in the headstock and mandrel drive circuits, as shown in Fig. 3, and the tumble gear lever 36a, Pig. 2, set to wind right closing limit switch L810, operation of the head stock drive start button energizes relay HMRa which opens the normally closed contacts in the circuit to head stock left relay HML in the headstock drive circuit and closes contacts in circuits to chucking relay CRX and and solenoid 8V1 of the solenoid valve controlling the chucking device. The closing of the circuit by the start button also energizes headstock right relay HMR which closes the holding circuit around the starter button and actuates the motor switch through contact HMRa to start the motor HM to rotate the spindle in a direction to produce a right-hand wind. The mandrel drive .circuit is then closed by closing the start button therein which closes the circuit to mandrel motor relay MML. Relay MML closes the holding circuit about the start button and closes contacts in circuit to relay CRX and solenoid valve SVlt and also closes contact MMLa to the mandrel motor MM to start the same.

The traverse return motor TR is started by closing start button in the circuit to relay TRM. Actuation of relay TRM closes the holding circuit around the start button and closes contacts in the relay CRX and solenoid 8V1 circuits and also closes contact TRMa to start the traverse return motor TR.

With the motors in operation the winding spindle is reset into its normal starting position. This is accomplished by holding the reset switch closed which closes the circuit through the normally closed contact on relay CRS to energize the relay CRR. Relay CRR opens contact CRRa in the circuit with rheostat R2 to the brake B1 in the spindle drive mean and closes CRRb and CRRc in the circuit of potentiometer P1 and circuit for clutch C1 of the starting circuit and also closes con tact CRRa' in potentiometer P2 and circuit for brake B1. The spindle is slowly inched to its normal starting position. This is accomplished, in the illustrated form of the invention, by connecting a generator G1, as shown in Fig. 2, driven by the spindle and feeding the generated voltage to a bridge circuit BR]. which in turn controls the electronic control relay ECR1 in accordance with a predetermined spindle speed. Since the speed of the spindle is below that set, the electronic control relay ECRl is energized to close the circuit to the clutch through contacts ECRla to rotate the spindle. When the speed of the spindle exceeds the desired amount, the relay ECRl opens contact ECRia in the circuit to the clutch C1 and closes the circuit through ECRlb to the brake B1 so that the spindle is slowed down and this is repeated .5 the ".pinzile is inchsd t w rd the pre determined position, in which position the lug 40 (Fig.

2) on the cam plate 41 on the spindle engages limit switch LS6 and closes the circuit to energize relay CRS. Relay CRS, when actuated, opens the circuit to relay CRR which opens contacts CRRb in the clutch circuit, closes a circuit through CRRa in the brake circuit and closes a holding circuit to relay CRS around limit switch LS6 thus stopping the spindle in a predetermined startin g position.

The mandrel is moved to winding position by actuating return switch which energizes relay TEI. Relay TEX closes the circuit to the tailstock motor through contacts TEld to rotate it in' the direction to move the tailstock and mandrel toward the chuck and opens contacts TEIa to the brake in the normally operated circuit to brake B3 and closes contact TEIb in the circuit including potentiometer P4 to brake B3 which is controlled by normally open limit switches LS3a and LSSa. It also closes the contacts TEIc (assuming selector switch SS3 is in automatic position) in the automatic return circuit containing limit switch LS1 and rheostat R6 to energize clutch C4 in the carriage return circuit to return the carriage to starting position.

When the tailstock has moved in a predetermined amount, it actuates LS8 setting up the control of the clutch and .brake in response to the operation of the electronic relay ECR2 to control the forward speed. Relay ECR2 is controlled similarly to relay ECRl by having a generator G2 (Fig. 2) driven in accordance with the forward movement of the tailstock. The generated voltage is fed to bridge BRZ which in turn centro-ls relay ECR2. Contact ECR2a is closed at speeds below the predetermined speed and contact ECRZb is opened at speeds below the predetermined speeds. Thus, the clutch C3 and brake B3 are controlled through these contacts until the mandrel carried by the tailstock is slowly moved into engagement with the chuck, whereupon limit switch LS3 is contacted and opens the circuit through potentiometer P3 to clutch C3 and applies through contact LS3a the brake B3 to stop the tailstock in its predetermined position with the mandrel engaging the chuck.

The machine is ready now for a winding operation and one end of the stock is passed under the traverse carriage roller 38 and is inserted into the normally open chuck. The chuck switch is closed, energizing relay CRX and solenoid valve SVl, which solenoid valve causes the fluid flow into cylinder 25 to operate the chuck and clamp the end of the work. Relay CRX closes. the holding circuit around the chuck switch, closes the contact in the circuit to CR4 and closes the contact in circuit relay CR1. The lay-down switch is also closed to energize CR4 and solenoid valve 8V4 which causes fluid to cylinder 47 to move the lay'down roll from its normally raised position, shown in dot lines, into operating position, shown in full lines in Fig. 7 wherein it engages the mandrel. Relay CR4 also closes the contact CR4a in the circuit through rheostat R1 to clutch C1.

The machine is now ready to start the coiling operation and the coil start switch is held closed, energizing relay CRCl. This opens the normally closed contact CRClla in the brake circuit B3, closes contact to limit switch LS5 and closes contact CRClb in the clutch circuit including rheostat R1. Since contact CR4o is closed, the clutch C1 is energized to start the winding with the chuck and mandrel in the position shown in Fig. 8.

After a predetermined partial rotation of the spindle sufficient to form the required fiat bottom for the spring, the lug 49 on the cam plate 48 on the spindle 13 engages limit switch LS5 and closes the same, and cornpletes the circuit to relay CR1. Relay CR1 closes the holding circuit around the coil start switch, opens cont ct CRla in the carriage return circuit and closes con- TRY; in h: circrit for clutch C2. which drives gears and starts the carriage moving to lay the coils of stock in a predetermined manner upon the freely rotatable mandrel as the stock rotates the mandrel.

When the carriage has moved the required distance to wind the spring, as shown in Fig. 9, it contacts limit switch LS2 (Fig. 2) and opens the circuit through relay CR1 which opens contacts CR1]; in the circuit for clutch C2 as well as the circuit to limit switch LS5 and closes contacts CRM in the carriage return circuit to clutch C4 to return the carriage when relay TEI is energized and closes contact TEIc as noted above.

When it is desired to strip the coil after it is wound, the strip switch is held closed energizing relay TEO. Energization of the relay T E closes the circuit through contact TEOc to the motor TE to move the tailstock in reverse direction. It also opens the contact TEQa in the normal circuit through rheostat Rd to the brake B3 and closes contact TEOb in the circuit for the brake which is controlled by limit switch LS4 and also closes contacts to time delay relay TD3 and TD3 closes the circuit to time delay relay TD1. Time delay relay TD?) opens the circuits to relay TEI and time delay relay TD2. Relay TDI closes contact TDla in the circuit with rheostat R3 and clutch C5 starting the mandrel rotating with respect to the coil held by the stationary chuck and in a direction to cause the coil to release its grip on the smooth surface of the mandrel. After a predetermined time interval, contact TDlb closes the circuit to rheostat R4 and clutch C3 which starts the tailstock moving out away from the chuck. Fig. shows the mandrel starting back with the chuck still holding the end of the stock. After the tailstock has moved part-way back, see Fig. 2, it will engage limit switch LS? which breaks the circuit to the solenoid valves SVI and SV4 causing the chuck and the lay-down roll to return to normal released and lifted positions and also breaks the circuit to CRX and CR4, causing the chuck to release the end of the spring and the lay-down roll to be raised out of contact and holding relation with the coil. Relay CR4 also opens the circuit to spindle clutch C1. The tailstock continues to retract the mandrel with the end of the spring engaging the stripper fingers 50 to remove the coil from the mandrel.

When the tailstock reaches its full back position in which the spring has been stripped from the mandrel, the tailstock engages the limit switch LS4 opening the circuit to relay TEO which also opens the circuit to time delay relays T133 and T31 and the circuits to clutch C3 and C5 and contact LS ia closes the circuit to brake B3 to complete the cycle of operation.

If a left-hand coil is to be wound, the selector switch SS is set in its lower or left wind position to reverse the motors HM and MM and tumble gear lever is shifted, closing LSli. The cycle and sequence of operations is the same as for winding a right-hand coil.

While the foregoing operations may be controlled automatically by means of an automatic controller actuating the switches, it is at present preferred to have the switches operated manually in order to effect a closer operational control over the machine.

Variations and modifications may be made within the scope of theclaims and portions of the improvements may be used without others.

We claim:

1. In a coil-forming machine, a smooth, freely rotatable mandrel; drive means; a rotatable spindle driven thereby and having a chuck thereon adapted to grip the end of a piece of stock to be coiled about the mandrel,

- the stock rotating the mandrel as it is coiled thereabout;

a feeding carriage having means engaging the stock; means driven by the spindle and including an electrically operated clutch for feeding the carriage along the mandrel as the stock is coiled 'thereabout; switch means controlled by the spindle for rendering the clutch operative after a predetermined partial rotation of said spindle during a coiling operation, comprising a stop switch for 8 t the spindle with a first rotary actuating cam member therefor, and a starting switch for the carriage with a second rotary actuating cam member therefor adjustable to vary its rotational phase relationship with respect to the first cam member determining the peripheral extent of the flat end portion of the coil.

2. In a coil forming machine having a spindle having a chuck thereon adapted to grip the end of a piece of stock to be coiled about a mandrel, drive means for the spindle including an electromagnetically operated clutch and an electromagnetically operated brake; loeating means operative during a partial rotation of the spindle to locate the spindle in a predetermined rotative position for the gripping of said stock by the chuck, said locating means including speed-responsive means actuated by the rotation of the spindle for controlling the operation of the clutch and brake to slowly rotate the spindle to said predetermined position; and means controlled by the rotative position of the spindle applying the brake and stopping the spindle when the spindle reaches said predetermined position.

3. In a coil forming machine having a spindle and a chuck thereon adapted to grip the end of a piece of stock to be coiled about a mandrci, means for locating the spindle in a predetermined rotative position comprising drive means for the spindle including an electromagnetically operated clutch and an electromagnetically operated brake; means including a generator actuated by the spindle for controlling the energization of the clutch and brake to slowly rotate the spindle to said predetermined position for the gripping of said stock by the chuck; and means controlled by the spindle for braking the spindle when the spindle reaches said predetermined position.

4. In a coil forming machine, a mandrel, a spindle having a chuck thereon adapted to grip the end of a piece of stock to be coiled about the mandrel, drive means for the spindle including an electromagnetically operated clutch and an electromagnetically operated brake; an electric circuit connected to said clutch and brake to control the operation thereof to inch the spindle slowly to a predetermined rotative position for the gripping of said stock by the chuck, said circuit including a generator driven by the spindle and means controlled thereby to cause operation of the clutch until the spindle speeds exceed the desired speed and then applying the brake until the speed is reduced below the desired speed; and means controlled by the spindle for opening said circuit and braking the spindle when the spindle reaches said predetermined position.

5. In a coil-forming machine, a smooth mandrel; a spindle having a chuck thereon adapted to grip the leading end of a piece of stock; means moving the mandrel into engagement with the chuck; means locating the spindle and chuck in a predetermined starting position to receive the leading end of the stock; drive means rotating the spindle and chuck to coil the stock around the mandrel, said drive means comprising an electromagnetic clutch and electromagnetic brake, said mandrel being freeturning and rotated by the stock as it is coiled whereby scoring of the mandrel by the stock is prevented; coillaying means driven from the drive means and guiding the stock along the mandrel to lay the coils with a predetermined pitch, said coil-laying means having an electromagnetic clutch between it and said spindle drive means, with electric circuit means operatively interconnecting said first-mentioned clutch and brake and said last-mentioned clutch for stopping the spindle at said starting position for gripping the stock and for then starting the spindle with said coil-laying means remaining at rest in starting position during said predetermined partial rotation of the spindle; coil shaping control means operative after a predetermined partial rotation of the spindle from starting position for actuating the last-named means whereby the flat bottom for the coil is formed, said coil meager;

shaping control means comprising a stop switch with a first rotary actuating cam member therefor controlled by the rotation of the spindle for deenergizing the clutch While energizing the brake; a starting switch with a second rotary actuating cam member therefor also controlled by the rotation of the spindle for energizing the coil-laying clutch to start the coil-laying, said second cam member being adjustable in its phase relationship with respect to the first cam member to vary the peripheral extent of the flat end of the coil; a lay-down roll engaging the trailing end of the coil to form the end thereof; means stopping the coil-laying means at the end of the coiling operation; separate drive means for returning the coil-laying means to starting position; means for stripping the coil from the mandrel including means holding the chuck against rotation and means for positively rotating and withdrawing the mandrel independently of the chuck with respect to the coil to strip the coil therefrom, said chuck and lay-down roll holding the coil during a predetermined initial withdrawing of the mandrel; means actuated in response to said predetermined withdrawal for releasing the chuck and lay-down roll from the coil; means thereafter engaging the coil and stripping the same from the mandrel during the completion of the withdrawal; and means stopping the mandrel in fully withdrawn position.

References Cited in the file of this patent UNITED STATES PATENTS Millett Feb. 9, Almond Jan. 1, Gruber Mar. 9, Horsley a Nov. 5, Lockwood May 17, Greenleaf Oct. 13, Rohlfing Apr. 6, Kaseberg Apr. 6, Williams Oct. 13, Dean Feb. 12, Gogan Oct. 22, Gogan Sept. 15, Lillquist Oct. 21, Glasner Oct. 21, Armstrong Aug. 15, Harding Jan. 9, Foster Dec. 11,

FOREIGN PATENTS Great Britain Mar. 29, 

